Passionate, brave and fiercely loyal, Margaret Kerr - a young woman estranged from her husband - is determined to play her part in saving Scotland from the hammer of Edward Longshanks - King of England and would-be King of the Scots. And so she travels to Stirling to discover why the informer upon whom the Scottish rebels depend has become unreliable. It is an important and difficult mission, for he who holds Stirling Castle holds Scotland, and with fresh English recruits marching forth, a bloody battle for the castle is imminent. As the Scots prepare to cast off the English yoke once and for all, Margaret soon realises she can trust no one, not even her closest friends. Is she prepared to give her life for her country?